I too am experiencing due dates changing. A few weeks ago I noticed that my bills due in May were changed to July. I changed them back to May. Today I went to pay one of those bills and found that they were changed to September. I changed them back to May. I have the subscription and always install the Quicken updates. Currently I am at R26.17, build 27.1.26.17.
I'm on the same build you are. Mine has appeared to be fixed for the last couple of updates. But, I have either paid my yearly ones that were jumping around or I deleted them and re-created them. That is the one way I got them to fix. The ones that kept doing what you describe had been memorized reminders for many years.
So instead of completely fixing the bug Quicken only fixed the code and not the data? To complete the fix I have to delete an recreate reminders? Are all reminders impacted or just some? This is not a solution and/or fix.
I'm not saying that since I don't work for them. Just noting what I've seen and what I did. I also created a PDF report of my reminders once I fixed them so I could go back and check to verify if they were moving around. I don't know for sure what they have done.
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